Polymer,method of its preparation, and electronic device

ABSTRACT

A polymer comprising structural units of the formula I has a number average molecular weight of less than 300.10 3  g/mole and a weight average molecular weight of less than 500.10 3  g/mole. A preferred example is a polyphenylene-vinylene. A composition of this polymer can be deposited on a substrate by means of inkjet printing excellently. This can be used for the manufacture of electroluminescent devices, in particular multicolor electroluminescent devices.

[0001] The invention relates to a polymer with structural units inaccordance with formula I,

[0002] in which

[0003] Ar is an aromatic cyclic system with 4 to 20 carbon atoms withoptionally a single or multiple substitution with a group chosen from anon-branched C₁-C₂₀-alkyl, C₃-C₂₀-alkoxy, C₁-C₂₀-alkylsulphate, abranched C₃-C₂₀-alkyl, phenyl, or benzyl group, and which may optionallycomprise up to 4 hetero atoms chosen from the group comprising oxygen,sulfur, and nitrogen in the aromatic cyclic system,

[0004] R₂ and R″₂ are chosen from the group comprising a hydrogen atomand a C₁-C₂₀-alkyl and a C₄-C₂₀-aryl group, which groups may optionallycomprise substituents.

[0005] The invention further relates to a composition.

[0006] The invention further relates to a method of preparing polymerswith structural units as defined by formula I, a composition of whichpolymers can be provided on a substrate by means of ink jet printing.

[0007] The invention also relates to the use of said composition.

[0008] The invention also relates to an electronic device.

[0009] Such a polymer is known from WO-A-99/21936. In the known polymer,the group

[0010] —Ar— is a multiply substituted phenyl group. The polymer is apolyphenylene-vinylene, which will also be referred to as PPVhereinafter. The polymer is prepared by a method which starts with amonomer of the formula Cl—CH₂—Ar—CH₂—Cl, in which Ar has the samemeaning as in the formula I. After addition of a base, polymerizationtakes place to a polymer having structural units —Ar—CHCl—CH₂—. Then theCl group is eliminated through heating. This method is known to thoseskilled in the art as the Gilch synthesis. The PPVs prepared in thismanner have electroluminescent properties and are used in light-emittingdiodes and picture screens for this reason. It is desirable in themanufacture of such picture screens to provide a layer of the PPVs bymeans of ink jet printing.

[0011] Experiments carried out by applicant have shown that a layer ofPPVs of the formula I cannot be provided on a substrate by means of inkjet printing without special measures.

[0012] It is a first object of the invention to provide a polymer of thekind mentioned in the opening paragraph, a composition of which can beprovided on a substrate by means of ink jet printing.

[0013] It is a second object of the invention to provide a compositionof the kind mentioned above which can be provided on a substrate bymeans of ink jet printing.

[0014] It is a third object of the invention to provide a method of thekind mentioned above by means of which the polymer according to theinvention can be prepared.

[0015] It is a fourth object of the invention to provide an electronicdevice of the kind mentioned above comprising the polymer of theinvention.

[0016] The first object is achieved in that the polymer has a numberaverage molecular weight which is below 300.10³ g/mole, and in that thepolymer has a weight average molecular weight which is below 500.10³g/mole. It was surprisingly found that compositions of the polymeraccording to the invention are well printable. Various problems,however, arise with compositions of the polymer having a higher numberaverage molecular weight. It was found first of all that the head of theprinting unit used for ink jet printing is clogged up very quickly andthus becomes useless. Secondly, a higher molecular weight is found tomake the elongational viscosity so high that no droplets are formedduring printing, but threads. This considerably slows down the printing.In addition, the risk of the polymer being deposited in an undesirablelocation on the substrate is considerably increased by the formation ofthreads. Thirdly, a layer of the polymer of a non-uniform thickness isoften obtained. The result of this is that the device will not meet therelevant specifications.

[0017] The inventors have observed that the invention is of particularimportance for conjugated polymers with a—conjugated—chain ofalternating single and double bonds which are delocalized. According tothe theory of organic chemistry, double bonds exist as a result ofoverlapping p-orbitals. The result of this is that a double bond lies ina flat plane and has a strongly reduced flexibility. According to amodel from the dynamics of polymeric liquids—the reptation model —,diffusion in a polymeric liquid takes place mainly in a one-dimensionalmanner in the direction of the chain. Owing to the smaller flexibilityof the conjugated chain and—probably—more densely packed polymer chains,the diffusion of the conjugated chain is thus less than that of thenon-conjugated chain. It is by no means surprising for these reasonsthat other polymers such as polyvinylcarbazoles, and diluted solutionsof precursor polymers known from EP-A-892028 behave differently. Indeed,the compositions known from EP-A-892028 with 0.75% by weight ofprecursor polymer, a usual concentration, are even found to be not orbadly printable by means of ink jet printing.

[0018] The polymer according to the invention preferably is a PPV.Examples thereof preferably comprise as the —Ar-group an aromatic groupchosen from: 1,4-phenylene, 2,6-naphthalenediyl, 1,4-naphthalenediyl,1,4-anthracenediyl, 2,6-anthracenediyl, 9,10-anthracenediyl,2,5-thienylene, 2,5-furanediyl, 2,5-pyrrolediyl,1,3,4-oxadiazole-2,5-diyl, 1,3,4-thiadiazole-2,5-diyl,2,5-benzo[c]-furanediyl, 2,5-benzo[c]-pyrrolediyl,2,5-benzo[c]thienylene, thieno[3,2-b]thiofene-2,5-diyl,pyrrolo[3,2-b]pyrrole-2,5-diyl, pyrene-2,7-diyl,4,5,9,10-tetrahydropyrene-2,7-diyl, 4,4′-biphenylene,phenantrene-2,7-diyl, 9,10-dihydrophenantrene-2,7-diyl,dibenzofurane-2,7-diyl, dibenzothiophene-2,7-diyl, carbazole-2,7-diyl,of which the nitrogen-containing groups may be substituted on thenitrogen atom with a C₁-C₂₂-alkyl or C₂-C₁₀-aryl group, while in allsaid groups the H atoms in the aromatic rings may be substituted by aC₁-C₂₂ linear or branched alkyl group, C₄-C₁₄-aryl group,electron-donating groups such as C₁-C₂₂ linear or branched alkoxy andalkylthio groups, and halogen atoms, or electron-attracting groups suchas cyano, nitro, and ester groups, while the C₁-C₁₋₄-aryl group itselfmay be substituted by electron-donating or electron-attracting groups.

[0019] By further preference, the —Ar group is an aryl-1,4-phenylenegroup, in which the aryl group is a phenyl, naphtyl, or biphenylyl groupwhich may or may not be substituted. In particular, the —Ar group ispresent in a copolymer, such as the copolymers of formula (1) and (2),in which OC₁₀ represents 3,7-dimethyloctyloxy, OC₄ represents2-methylpropoxy, and 0≦r≦1, r being preferably approximately equal to0.5:

[0020] The polymer may alternatively be, for example, apolythienylene-vinylene, which polymer is used as an organicsemiconductor in thin-film transistors. These and similar polymerscomprise the unit of formula IV chosen as their aromatic group —Ar—,

[0021] in which

[0022] X is chosen from the group comprising O, S, NR₆,

[0023] R₃ and R₁₃ may possibly be identical and are chosen from thegroup comprising the atoms of hydrogen, chlorine, bromine, fluorine, andiodine, and the C₁-C₄-alkyl, carbonitryl, trihalomethyl, hydroxy, nitro,amino, carboxyl, sulphoxyl, sulphonate, and carbonate groups, andsubstituted and non-substituted phenyl, alkylaryl and arylalkyl, alkoxy,and thioalkoxy groups, and

[0024] R₆ is chosen from the group comprising a hydrogen atom and aC₁-C₂₀-alkyl, aryl, C₁-C₂₀-alkylaryl, and arylalkyl group.

[0025] The polymer according to the invention with a number averagemolecular weight of below 300.10³ g/mole may be obtained inter aliathrough the preparation of the polymer of formula I from a polymer ofthe formula II, in which Z is equal to a halogen chosen from among F,Cl, Br, and I; whereupon an ultrasonic aftertreatment takes place of acomposition comprising the prepared polymer and a solvent.

[0026] It was found that the aftertreatment provides a decrease of theaverage molecular weight. The inventors suspect, without wishing to bebound by this supposition, that aggregates are destroyed and/orcrosslinks between chains are removed in the aftertreatment. Theultrasonic aftertreatment provides not only a decrease in the averagemolecular weight, but also a narrower molecular weight distribution. Acomposition comprising the polymer is found to be stable after theaftertreatment. It was further found that the ultrasonic aftertreatmenthas no adverse effect on the operation of an electronic device in whicha layer of the polymer, in particular of the PPV, is used. Theaftertreatment preferably lasts 10 to 20 minutes and is carried out at 0to 30° C. Preferably, Z is identical to Cl.

[0027] It is alternatively possible to obtain the polymer according tothe invention by a different synthesis route such as described inapplicant's application no. EP 00201911.5 (PHNL000311) not previouslypublished.

[0028] The polymer is made into a composition also comprising a solventso as to be provided as a layer on a substrate. It was found that thecomposition according to the invention does not suffer a stronglyincreased elongational viscosity. The composition behaves as a Newtonianliquid during printing. Furthermore, the composition preferablycomprises usual auxiliary substances such as wetting agents likeglycerin and diethylene-glycol. It is also possible to use a mixture ofsolvents. The composition may advantageously be made available in areservoir of an ink jet printer.

[0029] Preferably, the composition comprises between 0.5 and 2.0% byweight of the polymer, said polymer having a number average molecularweight of between 75.10³ and 300.10³ g/mole, and a weight averagemolecular weight of between 150.10³ and 500.10³. Experiments have shownthat such a composition has a reasonable to good printing quality. Ifthe polymer is a PPV, the printed layer is found to be suitable for useas an electroluminescent layer in an electroluminescent device. Byfurther preference, the composition comprises 1.0 to 1.5% by weight ofthe polymer, said polymer having a number average molecular weight ofbetween 75.10³ and 225.10³ g/mole, and a weight average molecular weightof between 150.10³ and 450.10³. Such a composition has a good printingquality. The electroluminescent device manufactured therewith provides aluminescence which complies with the requirements set.

[0030] The object of providing an electronic device is achieved in thedevice according to claim 9. This device is especially characterized inthat the polymer has a number average molecular weight below 300.10³g/mole. It is possible because of this comparatively low molecularweight to provide the layer of the polymer by means of ink jet printing.The layer can be provided in a desired pattern in this manner. It ispossible, moreover, to provide several patterns next to one another onthe substrate. An electroluminescent device with more than one color canbe obtained in this manner. For example, a first pattern comprises a PPVwhich emits yellow light; a second pattern comprises a PPV which emitsgreen light, and a third pattern comprises a PPV which emits red light.Such PPVs are known per se. It is furthermore possible for a firstpattern to comprise a PPV, while a second pattern comprises a differentelectroluminescent material, such as a polyfluorine. Such polyfluorinesare also known per se.

[0031] These and other aspects of the polymers, the composition, themethod, and the electronic device according to the invention will beexplained in more detail below with reference to a Figure, a Table, anda description of the Figures, in which:

[0032] Table 1 lists the printing properties of compositions accordingto the invention, and FIG. 1 is a diagrammatic cross-sectional view of afirst embodiment of the electronic device.

[0033] Embodiment 1

[0034] A polymer of the formula (1) in which —OC₁₀ represents3,7-dimethyloctyloxy, and r is 0.5, is prepared by a method comparableto the method known from WO99/21936. This polymer will also be referredto hereinafter as NRS—PPV.

[0035] The NRS—PPV has a number average molecular weight M_(a) ofapproximately 9.10⁵ g/mole, and a weight average molecular weight M_(w)of approximately 2.10⁶ g/mole. It is used in a 1.2% by weight solutionin toluene. This is found to be not printable. A vessel containing thesolution is placed in an ultrasonic device which is commerciallyavailable under the designation Bransonic B32 for an aftertreatment atroom temperature. The aftertreatment is carried out during a period of 4hours. The treatment is interrupted every hour for determining themolecular weight. After two hours, M_(n) is 3.9.10⁵ g/mole and M_(w) is8.9.10⁵ g/mole. The solution is found to be somewhat printable. Afterfour hours, M_(n) has become 2.3.10³ g/mole and M_(w) 6.0.10³ g/mole.The solution is found to be reasonably printable. This treatment isindicated in Table 1 as “soft US”, accompanied by the duration of thetreatment.

[0036] Embodiment 2

[0037] A vessel with an untreated solution of NRS—PPV in anisole wasplaced in an ice bath. The solution, no. 25 in Table 1, had an Mn valueof 4.5.10⁵ g/mole and an M_(w) value of 5.3.10⁵ g/mole. This solutionwas first subjected to a soft US treatment for seven hours. Then a rodsystem was added to the vessel for an ultrasonic treatment. The rodsystem was a Branson Sonifier 450. The solution was subjected to anultrasonic treatment at a power of 280 W for 13 hours. The treatment wascarried out in a pulsatory manner, ultrasonic vibrations being generatedduring 60% of the time. Afterwards the number average molecular weightand the weight average molecular weight were determined. The resultswere: M_(n)=170.10³ g/mole, M_(w)=110.10³ g/mole, and the solution waswell printable. This treatment was denoted “harsh US” in Table 1, withthe treatment duration in hours.

[0038] Embodiment 3

[0039] An ink reservoir of an ink jet printer was filled with acomposition of a PPV treated in accordance with embodiment 1,approximately 1% by weight of PPV being present. The ink reservoir wasplaced in an ink jet printer with a single-nozzle piezoelectric ink jethead with a nozzle diameter of 50 μm (supplied by Microdop GmbH).

[0040] Printing was carried out by means of the ink jet printer on aglass substrate covered with a layer of indium-tin oxide (ITO) andfurther provided with a relief pattern of lines and cavities. Saidrelief pattern was formed through the application, exposure, anddevelopment of a photoresist such as the AZ 4562 photoresist fromHoechst. The distance between the substrate and the nozzle of the inkjet head was set for 1.0 mm, while the ink jet head was moved parallelto the lines of the relief pattern and was positioned above the centerof a depression to be filled between the lines. The initial averageheight of a liquid layer deposited by the ink jet head h_(ini) was equalto f.V/U.B, in which f is the ink jet droplet frequency, V is thedroplet volume, U is the velocity of passage of the substrate withrespect to the ink jet head, and B is the width of the depressionbetween the lines. In a first example of printing of the NRS—PPVsolution, f, V, U, and B were set as follows: f=300 Hz, V=220 pl, U=0.03m/s, and B=260 μm, which resulted in a hini value of 8.5 μm. It wassubsequently tested whether the composition could be printed.

[0041] The result is given in Table 1. Not printable means therein thatno stable formation of droplets was possible. The printer head formedthreads, e.g. droplets with filaments. These filaments broke up intoundesirable small satellite droplets and may thus strongly interferewith the landing position of the droplet. As the ratio M_(n)/M_(w)increased, the length of the filament increased. The influence of thehigh M_(w) was so strong in some cases that no drop emerged from theprinting head at all. TABLE 1 printing quality of compositions after anultrasonic treatment, soft US and harsh US denoting the types ofultrasonic treatment as discussed in embodiments 1 and 2, defined inhours, while the molecular weights M_(w) and M_(n) are given in g/mole.Soft Harsh Concentration Viscosity Viscosity US US No. Solvent [g/l]40s-1 500s-1 [h] [h] M_(w)/10³ M_(n)/10³ Printing Quality 1 tetraline8.81 11.6 11.0 21 10 170 90 Good 2 phenetole 9.92 7.5 7.1 22 20 190 110Good 3 4-methyl-anisole 9.24 10.9 8.5 14.5 12 250 130 Good 4 anisole7.56 8.4 6.8 23 0 370 150 Good 5 anisole 11.47 12.4 9.3 29 7.5 265 150Good 6 anisole 8.86 8.5 7.7 7 13 310 170 Good 7 4-methylanisole/o- 8.408.7 8.2 16 12 350 170 Good xylene 3:1 8 anisole 8.80 11.3 9.6 32 0 400180 Good 9 o-xylene 7.93 9.5 8.3 22 13 390 180 Good 10 anisole/o-xylene1:1 11.7 13 12.5 23 24.5 380 190 Good 11 anisole/o-xylene 1:1 8.1 8.88.6 9.5 12 400 190 Good 12 o-xylene 7.81 9.4 9.6 16.5 20 400 200 Good 13anisole/o-xylene 8.89 9.3 9.3 15 10 450 210 Good 14 o-xylene/anisole8.98 11.9 11.4 13.5 30 440 215 good 15 toluene 7.81 8.7 8.1 21 0 490 220Reasonable 16 toluene 5.99 6.5 6.1 4 0 600 230 Reasonable 17 o-xylene9.00 17.3 16.3 52 0 520 240 Moderate 18 anisole/o-xylene 3:1 8.29 13.312.0 20 0 500 250 Not printable 19 anisole/o-xylene 1:1 8.89 23.4 19.19.5 0 690 290 Not printable 20 toluene 6.72 14.7 4 0 880 310 Notprintable 21 toluene 6.75 18.1 3 0 980 320 Not printable 22 toluene 5.997.60 7.12 2 0 890 390 Moderate 23 toluene 6.85 16.1 2 0 840 400 Notprintable 24 toluene 6.52 25.2 1 0 1100 420 Not printable 25 anisole 4.311.0 11.7 0 0 530 450 Not printable

[0042] Embodiment 4

[0043] Of the above experiments, those numbered 11, 13, and 19 wererepeated, a multinozzle ceramic printing head with 64 nozzles being usedfor printing, each nozzle having a diameter of 50 μm. The results werefound to be unchanged.

[0044] Embodiment 5

[0045]FIG. 1 diagrammatically and in cross-section shows a firstembodiment of the electronic device 10. This device 10 comprises asubstrate 11, a first electrode layer 12, a first relief structure 13, ahole injection layer 14, an electroluminescent layer 15, and a secondelectrode layer 16. The substrate 11 comprises soda lime glass with athickness of 1.1 mm. The first electrode layer 12 of ITO is provided ina conventional manner on the substrate 11 in a pattern of 280 μm widelines and 30 μm wide openings. The first electrodes are thus obtained inthe form of row electrodes. These row electrodes act as the anodes ofthe electroluminescent elements 1.

[0046] The substrate is subsequently covered with a layer of a negativephotoresist AZ5218-e (AZ Hoechst) by means of spin coating (1000 rpm).The photoresist is irradiated in a pattern by means of a mask. Thephotoresist has a pattern of lines and openings of 20 and 290 μm,respectively, which pattern is at right angles to the row electrodes inthe vicinity (40 μm interspacing). A dose of 230 mJ/cm² is used for theexposure. Then the photoresist is cured at 110° C. for 10 minutes andexposed without a mask to a dose of 400 mJ/cm², whereupon thephotoresist is developed through the use of a 1:1 AZ developer: DI waterdeveloper during a period sufficient for obtaining a negative angle of45°. Then the entire assembly is given an aftertreatment at 100° C. for15 minutes. The result is a relief structure 13 of lines and openings,with a line width of 30 μm and openings of 280 μm. The openings aresituated above the first electrodes in this case. Each line has theshape of an upside-down trapezium, measuring 30 μm at the top and 20 μmat the base. The height of the relief structure 13 is 5.0 μm.

[0047] A solution of poly-3,4-ethylenedioxythiophene (PEDOT) andpolystyrenesulphonic acid in water with a 3% solids content is providedover the relief pattern by means of spin coating at 2000 rpm. Thisresults in a wet layer with an average thickness of 8.3 μm. Duringspincoating, the wet layer is dried at 130° C. for 3 minutes. Thisresults in a patterned hole injection layer 14 of PEDOT with a thicknessof 250 nm and a square resistance of 100 MΩ/square.

[0048] Subsequently a solution of 0.6% by weight of the ultrasonicallytreated NRS—PPV is provided by means of ink jet printing as described inembodiment 3. The electroluminescent layer 15 is formed by the ink jetprinting process.

[0049] Then a 3 nm thick layer of Ba and a 200 nm thick layer of Al isdeposited, together forming the second electrode layer 16, on theelectroluminescent layer 15. During this deposition, the reliefstructure 13 serves as a shadow mask. The second electrode layer 15forms a plurality of column electrodes (cathodes).

[0050] The electroluminescent device 10 thus obtained is packed in anenvelope which is sealed off by means of an epoxy glue. A quantity ofBaO is present in the envelope so as to act as a water getter.

[0051] Embodiment 6

[0052] Embodiment 5 is repeated, an ultrasonically treated solution ofthe NRS/PPV having formula (1) being printed in a first, third, andfifth cavity. Subsequently an ultrasonically treated solution of the PPVhaving formula (2) is printed in a second, fourth, and sixth cavity. Thecavities in this case have dimensions of 60 by 60 μm. The result is atwo-color device, the first, third, and fifth cavities emitting yellowlight during operation (λ=590 nm), and the second, fourth, and sixthcavities emitting green light during operation (λ=550 nm). Alternativeembodiments printing in three or more colors are also possible on thebasis of this principle. It is furthermore possible that not only PPVs,but also other electroluminescent polymers such as polyfluorines areused.

1. A polymer with structural units in accordance with formula I,

in which Ar is an aromatic cyclic system with 4 to 20 carbon atoms withoptionally a single or multiple substitution with a group chosen from anon-branched C₁-C₂₀-alkyl, C₃-C₂₀-alkoxy, C₁-C₂₀-alkylsulphate, abranched C₃-C₂₀-alkyl, phenyl, or benzyl group, and which may optionallycomprise up to 4 hetero atoms chosen from the group comprising oxygen,sulfur, and nitrogen in the aromatic cyclic system, R₂ and R″₂ arechosen from the group comprising a hydrogen atom and a C₁-C₂₀-alkyl anda C₄-C₂₀-aryl group, which groups may optionally comprise substituents,characterized in that the polymer has a number average molecular weightwhich is below 300.10³ g/mole, and in that the polymer has a weightaverage molecular weight which is below 500.10³ g/mole.
 2. A polymer asclaimed in claim 1, characterized in that the number average molecularweight lies between 75.10³ and 225.10³ g/mole, and in that the weightaverage molecular weight lies between 150.10³ and 450.10³ g/mole.
 3. Apolymer as claimed in claim 1, characterized in that —Ar— in formula (1)stands for:

in which R₅, R′₅, R″₅, and R′″₅ are chosen from the group comprising theatoms of hydrogen, chlorine, bromine, fluorine, and iodine, and theC₁-C₄-alkyl, carbonitryl, trihalomethyl, hydroxy, nitro, amino,carboxyl, sulphoxyl, sulphonate, and carbonate groups, and optionallysubstituted phenyl, alkylaryl, and arylalkyl, alkoxy, and thioalkoxygroups.
 4. A polymer as claimed in claim 1, characterized in that thepolymer is obtainable through: preparation of the polymer havingstructural units in accordance with formula I from a polymer havingstructural units in accordance with formula II, in which Z is a halogenchosen from F, Cl, Br, and I; and subsequently an ultrasonicaftertreatment of a composition comprising the prepared polymer and asolvent.


5. A composition comprising a solvent and a polymer as claimed in anyone of the preceding claims.
 6. A composition as claimed in claim 5,characterized in that the polymer is present in a concentration ofbetween 0.5 and 2.0% by weight, wherein the number average molecularweight of the polymer is greater than 75.10³ g/mole and the weightaverage molecular weight of the polymer is greater than 150.10³ g/mole.7. A method of preparing polymers defined by the formula I, acomposition of which polymers can be provided on a substrate by means ofink jet printing, which method comprises the steps of: preparing thepolymers with a number average molecular weight of more than 300.10³g/mole, and an ultrasonic aftertreatment in which the number averagemolecular weight drops to below 300.10³ g/mole.
 8. The use of thecomposition as claimed in claim 5 or 6 for ink jet printing of a layerof a polymer comprising structural units in accordance with formula I ona substrate.
 9. An electronic device provided with a patterned layercomprising a polymer with structural units of the formula I on asubstrate,

in which Ar is an aromatic cyclic system with 4 to 20 carbon atoms withoptionally a single or multiple substitution with a group chosen from anon-branched C₁-C₂₀-alkyl, C₃-C₂₀-alkoxy, C₁-C₂₀-alkylsulphate, abranched C₃-C₂₀-alkyl, phenyl, or benzyl group, and which may optionallycomprise up to 4 hetero atoms chosen from the group comprising oxygen,sulfur, and nitrogen in the aromatic cyclic system, R₂ and R″₂ arechosen from the group comprising a hydrogen atom and a C₁-C₂₀-alkyl anda C₄-C₂₀-aryl group, which groups may optionally comprise substituents,characterized in that the polymer has a number average molecular weightwhich is below 300.10³ g/mole, and in that the polymer has a weightaverage molecular weight which is below 500.10³ g/mole.
 10. Anelectronic device as claimed in claim 9, in which —Ar— represents:

in which R₅, R′₅, R″₅, and R′″₅ are chosen from the group comprising theatoms of hydrogen, chlorine, bromine, fluorine, and iodine, and theC₁-C₄-alkyl, carbonitryl, trihalomethyl, hydroxy, nitro, amino,carboxyl, sulphoxyl, sulphonate, and carbonate groups, and optionallysubstituted phenyl, alkylaryl and arylalkyl, alkoxy, and thioalkoxygroups.
 11. An electronic device as claimed in claim 10, characterizedin that a second patterned layer is present on the substrate in additionto the —first—patterned layer, which second layer comprises a differentelectroluminescent material than the first layer and is provided bymeans of ink jet printing, and the device comprises a first and a secondelectroluminescent element, the first element comprising the firstpatterned layer and emitting light of a first wavelength duringoperation, and the second element comprising the second patterned layerand emitting light of a second wavelength during operation.